1. Field
The present invention relates to a pixel and an organic light emitting display using the same, and more particularly, to a pixel capable of simplifying the structure thereof and an organic light emitting display using the same.
2. Description of the Related Art
In general, a pixel of an organic light emitting display includes a thin film transistor (TFT) and a capacitor. The TFT includes a semiconductor layer for providing a channel region and source and drain regions, a gate electrode provided on the semiconductor layer of the channel region and electrically insulated from the semiconductor layer by a gate insulating layer, and source and drain electrodes respectively connected to the semiconductor layer of the source and drain regions. The capacitor includes two electrodes and a dielectric layer interposed between the two electrodes.
Among various types of flat panel displays (FPDs), an organic light emitting display displays images using organic light emitting diodes (OLEDs) that generate light by the re-combination of electrons and holes. The organic light emitting display has a high response speed and is driven with low power consumption.
The organic light emitting display includes a plurality of pixels arranged at the crossing regions of a plurality of data lines, scan lines, and power source lines in a matrix. Each of the pixels includes an organic light emitting diode (OLED), at least two transistors including a driving transistor, and at least one capacitor.
The above-described organic light emitting display has low power consumption. However, the amount of current that flows to the OLED changes in accordance with a variation in the threshold voltage of a driving transistor included in each of the pixels so that non-uniformity in display is caused. That is, the characteristic of the driving transistor changes in accordance with the manufacturing process variables of the driving transistor included in each of the pixels. Generally, it is very difficult to make all of the transistors of the organic light emitting display have the same characteristics in current processes so that a variation in the threshold voltage of the driving transistor is generated.
In order to solve the above-described problem, a method of adding a compensating circuit including a plurality of transistors and capacitors to each of the pixels has been suggested. The compensating circuit included in each of the pixels changes a voltage corresponding to the threshold voltage of the driving transistor to compensate for the variation in the threshold voltage of the driving transistor. However, because the compensating circuit typically adds no less than six transistors in a pixel, the structure of the pixel becomes more complicated. In addition, the probability of erroneous operations increases due to the increased number of transistors included in the pixel resulting in deteriorated yield.